Robot cleaner, docking station, robot cleaner system including robot cleaner and docking station, and method of controlling robot cleaner

ABSTRACT

A robot cleaner system is described including a docking station to form a docking area within a predetermined angle range of a front side thereof, to form docking guide areas which do not overlap each other on the left and right sides of the docking area, and to transmit a docking guide signal such that the docking guide areas are distinguished as a first docking guide area and a second docking guide area according to an arrival distance of the docking guide signal. The robot cleaner system also includes a robot cleaner to move to the docking area along a boundary between the first docking guide area and the second docking guide area when the docking guide signal is sensed and to move along the docking area so as to perform docking when reaching the docking area.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation application filed under 35 USC1.53(b) claiming priority benefit of U.S. Ser. No. 12/801,575 filed inthe United States on Jun. 15, 2010, which claims the benefit of U.S.Patent Application No. 61/213,569, filed on Jun. 19, 2009 and KoreanPatent Application Nos. 2009-0075963, filed on Aug. 18, 2009 and2010-0019376, filed on Mar. 4, 2010, in the Korean Intellectual PropertyOffice, the disclosure of which are incorporated herein by reference.

BACKGROUND

1. Field

One or more embodiments of the present disclosure relate to a robotcleaner system including a robot cleaner and a docking station.

2. Description of the Related Art

The term “robot cleaner” refers to a device to perform a cleaningoperation such as to suck dust, foreign matter or the like from a floorwhile traveling in a working area having a predetermined range withoutuser manipulation. The robot cleaner measures distances to obstaclessuch as furniture, office supplies or walls located within the workingarea using a sensor or a camera, and performs a predetermined operationusing the measured information while traveling without collision withthe obstacles.

The robot cleaner automatically cleans while autonomously moving in anarea to be cleaned and then moves to a docking station in order tocharge a battery of the robot cleaner or to allow for disposal of dustcontained in the robot cleaner.

SUMMARY

Therefore, it is an aspect of the present disclosure to provide a robotcleaner guided to a docking position to be docked without an overlappingarea where a plurality of docking signals overlap, a docking station, arobot cleaner system including the robot cleaner and the dockingstation, and a method of controlling the robot cleaner.

It is another aspect of the present disclosure to provide a robotcleaner to measure the period of a docking signal so as to detect areflected wave, a docking station, a robot cleaner system including therobot cleaner and the docking station, and a method of controlling therobot cleaner.

It is another aspect of the present disclosure to provide a robotcleaner configured to match a plurality of docking signals to the samedata codes so as to indicate plural pieces of area information, adocking station, a robot cleaner system including the robot cleaner andthe docking station, and a method of controlling the robot cleaner.

Additional aspects of the disclosure will be set forth in part in thedescription which follows and, in part, will be obvious from thedescription, or may be learned by practice of the disclosure.

In accordance with one aspect of the present disclosure, there isprovided a robot cleaner system including: a docking station to form adocking area within a predetermined angle range of a front side thereof,to form docking guide areas which do not overlap each other on the leftand right sides of the docking area, and to transmit a docking guidesignal such that the docking guide areas are distinguished as a firstdocking guide area and a second docking guide area according to anarrival distance of the docking guide signal; and a robot cleaner tomove to the docking area along a boundary between the first dockingguide area and the second docking guide area when the docking guidesignal is sensed and to move along the docking area so as to performdocking upon reaching the docking area.

The docking station may transmit a docking signal to a central portionof a front side of a main body thereof within the predetermined anglerange so as to form the docking area.

The docking station may include first and second transmission units totransmit docking guide signals to both sides of a front portion of amain body thereof and a third transmission unit to transmit the dockingsignal to a central portion of the front side of the main body thereofwithin the predetermined angle range.

The first and second transmission units may include first and secondlight emitting units to generate docking guide signals and first andsecond shading plates to block some of the docking guide signals passingthrough a first lens unit or a second lens unit so as to reducespreading angles of the docking guide signals, respectively.

The robot cleaner system may further include first and second lens unitsprovided outside the first and second light emitting units so as tospread the docking guide signals.

The third transmission unit may include a third light emitting unit togenerate the docking signal and a guide portion to guide a travelingdirection of the docking signal such that the docking signal is formedwithin the predetermined angle range.

In accordance with another aspect of the present disclosure, there isprovided a docking station including: at least one transmission unit toform a docking area within a predetermined angle range of a front sidethereof, to form docking guide areas which do not overlap each other onthe left and right sides of the docking area, and to transmit a dockingguide signal such that the docking guide areas are distinguished as afirst docking guide area and a second docking guide area according to anarrival distance of the docking guide signal, wherein the transmissionunit forms signals directed to the first docking guide area and thesecond docking guide area in the form of one signal and transmits thesignal.

The forming of the signals directed to the first docking guide area andthe second docking guide area in the form of one signal may includeforming a signal having a large amplitude, which reaches both the firstdocking guide area and the second docking guide area, and a signalhaving a small amplitude, which reaches only the second docking guidearea, in the form of one signal.

The forming of the signals directed to the first docking guide area andthe second docking guide area in the form of one signal may includeforming signals having different amplitudes in the form of one signal,such that only a signal having a large amplitude is analyzed as a databit in the first docking guide area and both the signal having the largeamplitude and a signal having a small amplitude are analyzed as the databit in the second docking guide area.

The transmission unit to transmit the docking guide signal may include alight emitting unit to generate the docking guide signal and a shadingplate to block some of the docking guide signal so as to reduce aspreading angle of the docking guide signal.

The docking station may further include a lens unit provided outside thelight emitting unit so as to spread the docking guide signal.

The docking station may further include a transmission unit to transmita docking signal to a central portion of a front side of a main bodythereof within a predetermined angle range such that a docking areawhich does not overlap the first docking guide area or the seconddocking guide area is formed.

The transmission unit to transmit the docking signal may include a lightemitting unit to generate the docking signal and a guide portion toguide a traveling direction of the docking signal such that the dockingsignal is formed at the central portion of the front side of the mainbody within the predetermined angle range.

In accordance with another aspect of the present disclosure, there isprovided a docking station including: at least one transmission unit toform a docking area within a predetermined angle range of a front sidethereof, to form docking guide areas which do not overlap each other onthe left and right sides of the docking area, and to transmit a dockingguide signal such that the docking guide areas are distinguished as afirst docking guide area and a second docking guide area according to anarrival distance of the docking guide signal, wherein delay times of aplurality of high periods included in the docking guide signal areadjusted to different lengths.

The adjusting of the delay times of the plurality of high periods to thedifferent lengths may include adjusting delay times of consecutive highperiods of the plurality of high periods to different lengths.

The docking station may further include a transmission unit to transmita docking signal to a central portion of a front side of a main bodythereof within a predetermined angle range such that a docking areawhich does not overlap the first docking guide area or the seconddocking guide area is formed, delay times of a plurality of high periodsincluded in the docking signal may be adjusted to different lengths.

The adjusting of the delay times of the plurality of high periods to thedifferent lengths may include adjusting delay times of consecutive highperiods of the plurality of high periods to different lengths.

The transmission unit to transmit the docking signal may include a lightemitting unit to generate the docking signal and a guide portion toguide a traveling direction of the docking signal such that the dockingsignal is formed at the central portion of the front side of the mainbody within the predetermined angle range.

The transmission unit to transmit the docking guide signal may include alight emitting unit to generate the docking guide signal and a shadingplate to block some of the docking guide signal so as to reduce aspreading angle of the docking guide signal.

The docking station may further include a lens unit provided outside thelight emitting unit so as to spread the docking guide signal.

In accordance with a further aspect of the present disclosure, there isprovided a method of controlling a robot cleaner, the method including:checking whether the robot cleaner needs to be docked at a dockingstation; moving the robot cleaner toward a boundary between a firstdocking guide area formed a predetermined distance or more from thedocking station and a second docking guide area formed within thepredetermined distance from the docking station, if the robot cleanerneeds to be docked; moving the robot cleaner along the boundary to reacha docking area formed at a central portion of a front side of thedocking station within a predetermined angle range, if the boundary issensed; and moving the robot cleaner along the docking area so as todock the robot cleaner at the docking station, if the robot cleanerreaches the docking area.

The sensing of the boundary may include moving the robot cleaner in adirection of the docking station if the robot cleaner is first locatedin the first docking guide area and determining that the robot cleaneris located at the boundary when the robot cleaner reaches the seconddocking guide area while moving in the direction of the docking station.

The sensing of the boundary may include moving the robot cleaner in adirection different from a direction of the docking station if the robotcleaner is first located in the second docking guide area anddetermining that the robot cleaner is located at the boundary when therobot cleaner reaches the first docking guide area while moving.

According to the embodiments of the present disclosure, since a dockingarea is formed by mounting a simple component in a docking station,manufacturing costs associated with components are reduced.

According to the embodiments of the present disclosure, since the periodof the docking signal is measured so as to distinguish the dockingsignal from a reflected wave, the robot cleaner is prevented from movingin an undesired direction. At this time, the docking signal is easilydistinguished from the reflected wave by changing the length of thedocking signal.

According to the embodiments of the present disclosure, the robotcleaner quickly checks area information of a docking guide signal bycontaining plural pieces of area information in one docking guidesignal.

BRIEF DESCRIPTION OF THE DRAWINGS

These and/or other aspects of the disclosure will become apparent andmore readily appreciated from the following description of theembodiments, taken in conjunction with the accompanying drawings ofwhich:

FIG. 1 is an appearance perspective view of a robot cleaner systemaccording to an embodiment of the present disclosure;

FIG. 2 is a perspective view of a robot cleaner according to anembodiment of the present disclosure;

FIG. 3A is a front perspective view of a docking station according to anembodiment of the present disclosure;

FIG. 3B is a back perspective view of a docking station according to anembodiment of the present disclosure;

FIG. 4 is an enlarged view of a transmission unit included in a dockingstation according to an embodiment of the present disclosure;

FIG. 5 is a control block diagram of a docking station according to anembodiment of the present disclosure;

FIG. 6 is a control block diagram of a robot cleaner according to anembodiment of the present disclosure;

FIG. 7 is a conceptual diagram illustrating an operation principle of arobot cleaner system according to an embodiment of the presentdisclosure;

FIG. 8 is a flowchart illustrating a docking process of a robot cleaneraccording to an embodiment of the present disclosure;

FIGS. 9A, 9B, 9C, and 9D are views illustrating a detection principle ofa reflected wave according to an embodiment of the present disclosure;and

FIGS. 10A, 10B, 10C, and 10D are views illustrating a principle ofmatching a plurality of docking signals to one data code and formingplural pieces of area information according to an embodiment of thepresent disclosure.

DETAILED DESCRIPTION

Reference will now be made in detail to the embodiments of the presentdisclosure, examples of which are illustrated in the accompanyingdrawings.

FIG. 1 is an appearance perspective view of a robot cleaner systemaccording to an embodiment of the present disclosure, and FIG. 2 is aperspective view of a robot cleaner according to an embodiment of thepresent disclosure.

FIG. 3A is a front perspective view of a docking station according to anembodiment of the present disclosure, FIG. 3B is a back perspective viewof a docking station according to an embodiment of the presentdisclosure, and FIG. 4 is an enlarged view of a transmission unitincluded in a docking station according to an embodiment of the presentdisclosure.

As shown in FIGS. 1 and 2, the robot cleaner system includes a robotcleaner 20 and a docking station 10 to charge a battery of the robotcleaner 20.

Referring to FIG. 2, the robot cleaner 20 includes a main body 22forming an appearance thereof, reception units 210 a to 210 d mounted onfront and back sides of the main body 22 to receive signals transmittedfrom the docking station 10, and driving wheels 24 mounted on a lowerside of the main body 22 to move the robot cleaner 20.

The reception units 210 a to 210 d of the robot cleaner 20 receive adocking signal or docking guide signals transmitted from the dockingstation 10. In the reception units 210 a to 210 d of the robot cleaner20 according to the embodiment of the present disclosure, two receptionunits are mounted on a central portion of the front side of the mainbody 22 and two reception units are mounted on both sides of the backportion of the main body 22, although other positions and quantities maybe used.

The driving wheels 24 of the robot cleaner 20 are mounted on the leftand right side of the main body 22 and are independently driven by amotor driving unit (not shown) to move the robot cleaner 20 in a desireddirection. A plurality of auxiliary wheels (e.g., casters) to supportthe main body 22 and smoothen traveling of the robot cleaner 20 may bemounted on the front and back sides of the driving wheels 24.

Referring to FIGS. 3A and 3B, the docking station 10 includes a mainbody 11 forming an appearance thereof and transmission units 110 a, 110b and 110 c mounted on the main body 11 to transmit the docking signaland the docking guide signals.

The first transmission unit 110 a and the second transmission unit 110b, to transmit the docking guide signals, are mounted on both sides of afront portion of an upper end of the docking station 10, and the thirdtransmission unit 110 c is mounted on a central portion of the frontside of the upper end of the docking station 10 to transmit the dockingsignal within a predetermined angle range.

A slip prevention pad 14 to prevent movement of the docking station 10is attached to a lower end of the docking station 10. The slipprevention pad 14 is made of a material (e.g., rubber) having a highcoefficient of friction. The slip prevention pad 14 includes a firstslip prevention portion 14 a obliquely extending in an oppositedirection of a docking direction of the robot cleaner 20, a second slipprevention portion 14 b obliquely extending in an opposite direction ofa separation direction of the robot cleaner 20, and a third slipprevention portion 14 c extending downward in a pin shape. In addition,a guide groove 15 is concavely formed in the lower end of the dockingstation 10 such that a connection terminal 242 (not shown) of the robotcleaner 20 is stably connected to a charging terminal 12 of the dockingstation 10.

The charging terminal 12 to charge the battery of the robot cleaner 20is provided on the lower end of the docking station 10. An embossedportion 12 a is provided on an upper surface of the charging terminal 12such that the connection with the connection terminal 242 (not shown) ofthe robot cleaner 20 becomes stable. A tact switch 13 pressed when therobot cleaner 20 enters the docking station 10 is mounted on the insideof the lower end of the docking station 10. When the tact switch 13 ispressed, power is applied to the charging terminal 12.

Referring to FIG. 4, in the transmission units 110 a to 110 c includedin the docking station 10, the first transmission unit 110 a and thesecond transmission unit 110 b are mounted on both sides of thetransmission unit 110 c to externally transmit the docking guidesignals, and the third transmission unit 110 c is mounted between thetransmission units 110 a and 110 b to transmit the docking signal withinthe predetermined angle range.

The first transmission unit 110 a and the second transmission unit 110 binclude a first light emitting unit 111 a and a second light emittingunit 111 b to generate the docking guide signals, a first lens unit 112a and a second lens unit 112 b to spread the docking guide signalsgenerated by the first light emitting unit 111 a and the second lightemitting unit 111 b, and a first shading plate 113 a and a secondshading plate 113 b mounted on the front side of the first lens unit 112a and the second lens unit 112 b to block some of the docking guidesignals passing through the lens units 112 a and 112 b so as to adjustspread angles of the signals, respectively.

Each of the first lens unit 112 a and the second lens unit 112 bincludes a 180-degree spread lens to adjust the spread angle of thesignal to 180° using a refractive index of the surface thereof. Outersurfaces of the first lens unit 112 a and the second lens unit 112 b arepolyhedral and grooves 115 a and 115 b having curved surfaces are formedin the inside thereof so as to better spread light.

The third transmission unit 110 c includes a third light emitting unit111 c to generate the docking signal, and a guide portion 114 a to guidea traveling direction of the docking signal such that the docking signalgenerated by the third light emitting unit 11 c is transmitted withinthe predetermined angle range. The guide portion 114 a is a slit whichis made of a material such as metal or a shading plate, through whichinfrared light may not pass, and thereby functions as an infrared lightblocking device.

Meanwhile, the first to third light emitting units 111 a to 111 cinclude infrared light emitting elements to generate infrared signals orLight Emitting Diodes (LEDs) to generate light beams.

FIG. 5 is a control block diagram of a docking station according to anembodiment of the present disclosure, and FIG. 7 is a conceptual diagramillustrating operation principle of a robot cleaner system according toan embodiment of the present disclosure.

As shown in FIG. 5, the docking station 10 includes the first and secondtransmission units 110 a and 110 b to transmit the docking guidesignals, the third transmission unit 110 c to transmit the dockingsignal, the charging terminal 12 to charge the battery of the robotcleaner 20, a power supply 130 to supply power to the charging terminal12, a docking sensor 120 to sense docking of the robot cleaner 20, and acontroller 140 to control the overall operation of the docking station10.

Referring to FIG. 7, the first transmission unit 110 a and the secondtransmission unit 110 b transmit a left-area signal (L-area and W₁-areasignal) and a right-area signal (R-area and W₂-area signal), both ofwhich are the docking guide signals, to docking guide areas,respectively. The left-area signal and the right-area signal aredistinguished from each other by a bit array. For example, the left-areasignal may be set to a bit array of “01” and the right-area signal maybe set to a bit array of “10”. The detailed description of the bit arrayof each area signal will be given later. Meanwhile, since the signalsare transmitted from the first transmission unit 110 a and the secondtransmission unit 110 b at the spread angle of about 90 degrees or lessby the shading plates 113 a and 113 b, a docking area (P area)distinguished from the docking guide areas is formed in a central areaof a front side of the docking station 10. Meanwhile, the docking area(P area) may be implemented as a non-signal area without a separatesignal. That is, the docking of the robot cleaner 20 may be controlledby stopping the operation of the third transmission unit 100 c andsetting an area, in which a signal is absent within a predeterminedangle range of the front side of the docking station 10, as the dockingarea.

The third transmission unit 110 c transmits a central-area signal, whichis the docking signal having a narrow transmission angle range, to thedocking area. The third transmission unit 110 c includes the guideportion 114 a to guide the docking signal, and the guide portion 114 aguides the traveling direction of the docking signal emitted from thethird light emitting unit 111 c such that the docking signal is formedin a predetermined area located at a central portion of a front side ofthe docking station 10.

The charging terminal 12 is connected to the connection terminal 242(not shown), which is electrically connected to a rechargeable battery(not shown) mounted in the robot cleaner 20. The charging terminal 12supplies power upon being connected to the connection terminal of therobot cleaner 20.

The power supply 130 supplies power to the charging terminal 12 so as tocharge the rechargeable battery of the robot cleaner 20.

The controller 140 is a microprocessor to control the overall operationof the docking station 10 such that power is supplied to the chargingterminal 12 through the power supply 130 according to a docking sensingsignal transmitted from the docking sensor 120.

The controller 140 adjusts the time lengths of high periods of data bitsof the docking signal transmitted from the first to third transmissionunits 110 a to 110 c such that the robot cleaner 20 distinguishes thedocking signal from a reflected wave. The robot cleaner 20 measures thetime length between a start point of a high period and a start point ofa subsequent high period of the docking signal transmitted from thedocking station 10 so as to determine the data bits. Referring to FIGS.9A to 9D, FIG. 9A shows the docking guide signal or the docking signaland FIG. 9B shows the reflected wave produced by reflection of thedocking signal or the docking guide signal from an obstacle. When asignal weakens as shown in FIG. 9B, the robot cleaner 20 measures timelengths A₂ and B₂ between a highest point of a first high period and ahighest point of a second high period which is a subsequent high periodso as to determine the data bits. At this time, it can be seen that thedistances A₁ and B₁ between the high periods and the distances A₂ and B₂between the high periods are equal to each other, respectively (A₁=A₂and B₁=B₂). Accordingly, the reflected wave produced by reflection ofthe docking signal or the docking guide signal from the obstacle may notbe recognized by the robot cleaner 20. Therefore, the controller 140adjusts delay times of the high periods of the data bits of the dockingguide signal or the docking signal to be different from each other.Referring to FIGS. 9C and 9D, if the signals in which the lengths of thehigh periods of the data bits are set to l and m are transmitted, timelengths between a start point of a high period and a start point of asubsequent period shown in FIG. 9C become A₃ and B₃. At this time, thedistances between the high periods of the reflected wave shown in FIG.9D become A₄ and B₄. Since the time lengths A₃ and B₃ and A₄ and B₄ arerespectively different from each other, the robot cleaner 20 mayrecognize the signal having the time lengths A₄ or B₄ different from thestored time lengths of the high periods as the reflected wave.

The controller 140 adjusts the data bits of the docking signaltransmitted from the third transmission unit 110 c or the docking guidesignals transmitted from the first transmission unit 110 a and thesecond transmission unit 110 b so as to contain different area signalsin one signal. For example, the first transmission unit 110 a does notseparately transmit a docking guide signal directed to the first dockingguide area and a docking guide signal directed to the second dockingguide area at a time interval. Instead, the first transmission unit 110a forms the signal directed to the first docking guide area and thesignal directed to the second docking guide area in the form of onesignal and transmits the signal to both the first docking guide area andthe second docking guide area, thereby shortening the periods of severalarea signals to the period of one signal. For example, as shown in Table1, a left-area bit array is “01”, a right-area bit array is “10”, and along-distance area bit array is “11”.

TABLE 1 Left area (short- Right area (short- Long-distance distancearea) distance area) area Data bit 01 10 11

At this time, referring to FIG. 10A, in the time length of the bit, ifit is assumed that the time length of the high period of a bit “0” is0.5, the time length of the low period of the bit “0” is 0.6, the timelength of the high period of a bit “1” is 0.5, the time length of thelow period of the bit “1” is 1.7, the time length of the high period ofa bit “11” is 0.5, and the time length of the low period of the bit “11”is 2.8, the first transmission unit 110 a and the second transmissionunit 110 b transmit one signal, in which the first docking guide signaland the second docking guide signal are included, as a docking guidesignal, as shown in FIGS. 10B and 10C. Referring to FIG. 10B, theamplitudes of the high periods are differently set. A signal having anamplitude a1 reaches the first docking guide area which is along-distance docking guide area and a signal having an amplitude a2reaches only the second docking guide area which is a short-distancedocking guide area.

For example, in the docking guide signal shown in FIG. 10B, since boththe high signal having the amplitude a1 and the high signal having theamplitude a2 reach the short-distance docking guide area, the highsignal having the time length of 0.5 (the high signal having theamplitude a1) and the subsequent low signal having the time length of0.6 are analyzed as the bit “0” and the subsequent high signal havingthe time length of 0.5 (the high signal having the amplitude a2) and thesubsequent low signal having the time length of 1.7 are analyzed as thebit “1”. Therefore, the total bit array is “01” and is analyzed as theleft-area short-distance docking guide signal. In addition, since thehigh signal having the amplitude a1 reaches the long-distance dockingguide area but the high signal having the amplitude a2 does not reachthe long-distance docking guide area, a signal shown in FIG. 10D reachesthe robot cleaner 20. Therefore, the high signal having the time lengthof 0.5 (the high signal having the amplitude a1) and the subsequent lowsignal having the time length of 2.8 are input, and information “11” isinput and is analyzed as the long-distance docking guide signal.

As another example, in the docking guide signal shown in FIG. 10C, sinceboth the high signal having the amplitude a1 and the high signal havingthe amplitude a2 reach the short-distance docking guide area, the highsignal having the time length of 0.5 (the high signal having theamplitude a1) and the subsequent low signal having the time length of1.7 are analyzed as the bit “1” and the subsequent high signal havingthe time length of 0.5 (the high signal having the amplitude a2) and thesubsequent low signal having the time length of 0.6 are analyzed as thebit “0”. Therefore, the total bit array “10” is analyzed as theright-area short-distance docking guide signal. In addition, since thehigh signal having the amplitude a1 reaches the long-distance dockingguide area but the high signal having the amplitude a2 does not reachthe long-distance docking guide area, a signal shown in FIG. 10D reachesthe robot cleaner 20. Therefore, the high signal having the time lengthof 0.5 (the high signal having the amplitude a1) and the subsequent lowsignal having the time length of 2.8 are input, and information “11” isinput and is analyzed as the long-distance docking guide signal.

As described above, if the short-distance docking guide signal and thelong-distance docking guide signal are transmitted in the period of onesignal, the robot cleaner 20 more quickly distinguishes the area,compared with the related art (a time difference between area signals isreduced).

FIG. 6 is a control block diagram of a robot cleaner according to anembodiment of the present disclosure.

The robot cleaner 20 includes reception units 210 a to 210 d to receivedocking signals or a remote control signal, an obstacle sensing unit 220to sense a peripheral obstacle, a driving unit 230 to drive the robotcleaner 20, a battery sensing unit 240 to sense the residue of thebattery, a storage unit 250 to store a traveling pattern or the like ofthe robot cleaner 20, and a control unit 260 to control the robotcleaner 20.

The reception units 210 a to 210 d receive the docking signalstransmitted from the first to third transmission units 110 a to 110 c ofthe docking station 10. The reception units 210 a to 210 d includeinfrared reception modules to receive the docking signals, and theinfrared reception modules include infrared reception elements toreceive infrared signals in a specific band.

The obstacle sensing unit 220 senses furniture, office supplies, walls,or other obstacles located within an area in which the robot cleaner 20travels. The obstacle sensing unit 220 may include all-direction sensorsand an analog/digital converter (not shown). The all-direction sensorsare provided on all sides of the robot cleaner and include RF sensors toemit RF signals and to detect signals reflected from peripheralobstacles. The obstacle sensing unit 220 receives the signals, convertsthe analog signals into digital signals through the analog/digitalconverter, and generates and transmits obstacle sensing signals to thecontrol unit 260.

The driving unit 230 controls the level of power applied to a motor (notshown) connected to the driving wheels 24 according to a control signaloutput from the control unit 260 so as to drive the robot cleaner 20.

The battery sensing unit 240 senses the charging residue of therechargeable battery 241 to supply driving power of the robot cleaner 20and transmits information about the charging residue to the control unit260.

The storage unit 250 stores an operating system to drive the robotcleaner 20, a traveling pattern, and the like, and stores locationinformation of the robot cleaner 20, obstacle information, and the like.A non-volatile memory such as a flash memory or an Electrically ErasableProgrammable Read-Only Memory (EEPROM) may be used as the storage unit.Data stored in the storage unit 250 is controlled by the control unit260.

The control unit 260 is a microprocessor to control the overalloperation of the robot cleaner 20 and determines whether the robotcleaner is docked at the docking station 10 according to a dockingrequest signal transmitted from the battery sensing unit 240. Thecontrol unit 260 determines the traveling direction of the robot cleaner20 according to the docking guide signals or the docking signalsreceived by the reception units 210 a to 210 d so as to dock the robotcleaner at the docking station 10. The detailed method of docking therobot cleaner 20 at the docking station 10 will be described later.

FIG. 8 is a flowchart illustrating a docking process of a robot cleaneraccording to an embodiment of the present disclosure.

The robot cleaner 20 set in a cleaning mode performs a cleaningoperation according to an input cleaning route or a randomly selectedcleaning route. The robot cleaner 20 checks whether the residue of thebattery is decreased to a predetermined level or less during thecleaning operation or whether the amount of accumulated dust or the likeis equal to or greater than a predetermined amount so as to checkwhether the robot cleaner 20 needs to be docked at the docking station10 (300 and 310).

Next, if the robot cleaner 20 needs to be docked, the cleaning mode isswitched to a docking mode. If the robot cleaner 20 is in the dockingmode, the robot cleaner 20 moves along a random route or a set route inorder to sense a docking signal or a docking guide signal (320).

Next, the robot cleaner 20 checks whether a first docking guide signalis sensed. The first docking guide signal is transmitted from the firsttransmission unit 110 a or the second transmission unit 110 b to along-distance area. The robot cleaner 20 determines that the robotcleaner is located in the first docking area which is a long-distancearea, when the first docking guide signal is sensed (330).

Next, when the first docking guide signal is sensed, the robot cleaner20 moves toward the docking station 10 to transmit the first dockingguide signal. The robot cleaner 20 moves in the transmission directionof the first docking guide signal when the reception units 210 a to 210d, mounted on the front side thereof, receive the signal (340).

Next, the robot cleaner 20 checks whether a boundary between the firstdocking guide area and the second docking guide area is sensed, whilemoving in the transmission direction of the first docking guide signal.The first docking guide area is a wide long-distance docking guide areaand the second docking guide area is a short-distance docking guidearea. The robot cleaner 20 continuously senses the docking guide signaleven when moving in the transmission direction of the first dockingguide signal and determines that the robot cleaner is located at theboundary when the sensed docking guide signal is changed from the firstdocking guide signal to the second docking guide signal (350).

Next, the robot cleaner 20 moves along the boundary when the boundarybetween the first docking guide area and the second docking guide areais sensed. The robot cleaner 20 may check whether the second dockingguide signal is a left-area signal or a right-area signal and determinea movement direction along the boundary according to the checked result.For example, the robot cleaner 20 moves to the right when the seconddocking guide signal which is the left-area signal is sensed whilemoving toward the docking station 10 such that the robot cleaner 20reaches a predetermined position from the front side of the dockingstation 10 (360).

Next, when the robot cleaner 20 senses the docking signal while movingalong the boundary, the robot cleaner is aligned with the dockingstation 10, is moved to a docking position of the docking station 10according to the docking signal, and is docked (370 and 380).

If the first docking guide signal is not sensed in Operation 330 but asecond docking guide signal is sensed, the robot cleaner 20 moves in adirection (e.g., an opposite direction) different from the transmissiondirection of the second docking guide signal (390 and 400).

Next, the robot cleaner 20 checks whether the boundary between the firstdocking guide area and the second docking guide area is sensed, whilemoving in the direction different from the transmission direction of thesecond docking guide signal. The robot cleaner 20 continuously sensesthe docking guide signal even when moving in the direction differentfrom the transmission direction of the second docking guide signal anddetermines that the robot cleaner is located at the boundary when thesensed docking guide signal is changed from the second docking guidesignal to the first docking guide signal (410).

Next, the robot cleaner 20 moves along the boundary when the boundarybetween the first docking guide area and the second docking guide areais sensed (360).

Next, when the robot cleaner 20 senses the docking signal while movingalong the boundary, the robot cleaner is aligned with the dockingstation 10, is moved to the docking position of the docking station 10according to the docking signal, and is docked (370 and 380).

If the first docking guide signal and the second docking guide signalare not sensed in Operations 330 and 390 and the docking signal issensed, the robot cleaner is aligned with the docking station 10, ismoved to the docking position of the docking station 10 according to thedocking signal, and is docked (420 and 380).

The method of controlling a robot cleaner according to theabove-described example embodiments may be recorded in computer-readablemedia including program instructions to implement various operationsembodied by a computer. The media may also include, alone or incombination with the program instructions, data files, data structures,and the like.

Examples of computer-readable media include magnetic media such as harddisks, floppy disks, and magnetic tape; optical media such as CD ROMdisks and DVDs; magneto-optical media such as optical disks; andhardware devices that are specially configured to store and performprogram instructions, such as read-only memory (ROM), random accessmemory (RAM), flash memory, and the like. Examples of programinstructions include both machine code, such as produced by a compiler,and files containing higher level code that may be executed by thecomputer using an interpreter.

The method of controlling a robot cleaner may be executed on a generalpurpose computer or processor or may be executed on a particular machinesuch as the robot cleaner described herein.

Although a few embodiments of the present disclosure have been shown anddescribed, it would be appreciated by those skilled in the art thatchanges may be made in these embodiments without departing from theprinciples and spirit of the disclosure, the scope of which is definedin the claims and their equivalents.

1. A docking station comprising: a first transmission unit to transmit afirst docking signal in a first direction, the first docking signalcomprising at least a first signal pulse and a second signal pulse,wherein a high period of the first signal pulse has a different timelength from a high period of the second signal pulse such that a robotcleaner is capable of distinguishing the first docking signal from areflected wave produced by reflection of the first docking signal froman obstacle.
 2. The docking station according to claim 1, furthercomprising a second transmission unit to transmit a second dockingsignal in a second direction, the second docking signal comprising atleast a first signal pulse and a second signal pulse, wherein a highperiod of the first signal pulse has a different time length from a highperiod of the second signal pulse such that the robot cleaner is capableof distinguishing the second docking signal from a reflected waveproduced by reflection of the second docking signal from an obstacle. 3.The docking station according to claim 2, wherein the first dockingsignal sensed by the robot cleaner located in a first short-distancedocking guide area is distinguished from the first docking signal sensedby the robot cleaner in a first long-distance docking guide area, andthe second docking signal sensed by the robot cleaner located in asecond short-distance docking guide area is distinguished from thesecond docking signal sensed by the robot cleaner in a secondlong-distance docking guide area.
 4. The docking station according toclaim 3, further comprising a third transmission unit to transmit athird docking signal in a direction towards a front side of the dockingstation between the first docking signal and the second docking signal.5. The docking station according to claim 4, wherein the firstshort-distance docking guide area and the second short-distance dockingguide area do not overlap each other.
 6. The docking station accordingto claim 1, wherein the adjusting of the delay times of the plurality ofhigh periods to the different lengths includes adjusting delay times ofconsecutive high periods of the plurality of high periods to differentlengths.
 7. The docking station according to claim 1, further comprisinga transmission unit to transmit a docking signal from a central portionof a front side of a main body thereof within a predetermined anglerange such that a docking area which does not overlap the first dockingguide area or the second docking guide area is formed, wherein delaytimes of a plurality of high periods included in the docking signal areadjusted to different lengths.
 8. The docking station according to claim7, wherein the adjusting of the delay times of the plurality of highperiods to the different lengths includes adjusting delay times ofconsecutive high periods of the plurality of high periods to differentlengths.
 9. The docking station according to claim 7, wherein thetransmission unit to transmit the docking signal includes a lightemitting unit to generate the docking signal and a guide portion toguide a traveling direction of the docking signal such that the dockingsignal is formed at the central portion of the front side of the mainbody within the predetermined angle range.
 10. The docking stationaccording to claim 1, wherein the transmission unit to transmit thedocking guide signal includes a light emitting unit to generate thedocking guide signal and a shading plate to block some of the dockingguide signal so as to reduce a spreading angle of the docking guidesignal.
 11. The docking station according to claim 10, furthercomprising a lens unit provided outside the light emitting unit so as tospread the docking guide signal.